Was there ever really a golden age? And if so, did people know it at the time? Are people even capable of recognizing a golden age when they're in the midst of one?

For Woody Allen, whose musical and cultural tastes run to the 1920s and '30s, these questions have probably fueled countless daydreams. And now out of all that rumination comes "Midnight in Paris," a movie that's loving and wistful and often hysterically funny.

Romance is built into the design. A screenwriter, who has always been nostalgic, visits modern-day Paris and falls through a ripple in time: On a Paris street, a clock strikes midnight, and a 1920s taxi cab drives up. Scott and Zelda Fitzgerald are inside, and they take him to a party.

Although at first the writer thinks these are faux Fitzgeralds and that he's at a costume party, he soon realizes that this is the real deal. He is surrounded by the music and styles he loves and is mingling with his idols and artistic heroes.

Our hero's dislocation keeps the movie as light as it needs to be. Meeting celebrities can be awkward enough, but meeting legends of the past -- the eagerness to please would be overwhelming. Yet always there is an edge of poignancy, too, because you are looking at the '20s through the eyes of a modern person, as a world that is, by definition, past. The past is always romantic because it's gone, just as the future is always frightening because you're gone.

There's an idea about Paris at work here, as well. Allen takes the notion of streets alive with the past and makes it literal in "Midnight in Paris," so that everything that has ever happened in this city never goes away. It's alive with parallel worlds -- which is sometimes how we feel when we visit great cities like Paris, Rome or New York.

Gil (Wilson) finds himself able to go back and forth between his own time and the '20s, and so we keep feeling the contrast. In the 21st century, he is engaged to an awful spoiled brat played without compromise by Rachel McAdams.

Meanwhile, in his nightly '20s rambles, he is falling in love with Adriana (Marion Cotillard), who is having an affair with Picasso.

As was the case with Penelope Cruz in "Vicky Cristina Barcelona," Woody Allen brings out, for the first time in an American film, the same fire and allure Cotillard has shown in her European work.

In the meantime, in between all the longing and wistfulness, this movie is sidesplitting, because Allen gets to tap into an inexhaustible source of comedy: Whenever he wants a laugh, or 10 laughs, he just introduces another writer or painter and plays to our expectations. Every scene, for example, involving Ernest Hemingway (Corey Stoll) is a scream, because Allen has him talk the way Hemingway wrote.

There is even a May Ray joke here. And if you know Luis Bunuel's "The Exterminating Angel," you'll fall out of your chair when Gil starts feeding him movie ideas.